How to make an object "move towards" another object
I'll admit it has been years since I've done any coding with the bge. But I would suggest looking up vectors. Get the vector from your empty to the object Then set the magnitude of that vector. Something like this:

vectTo = empty.getVectTo(object)

vectTo.magnitude = 2.0

empty.position += vectTo`


Like I said its been years and I don't have blender convinent to test (im really not sure that will compile) but something to that effect should work.